<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Vue的监听器Wacth</title>
</head>
<body>

<div id="app">
    <h1>{{title}}</h1>
    <h1>{{user.id}}==={{user.username}}==={{user.age}}</h1>
    <h3>{{user.person.pid}}</h3>
</div>

<script src="js/vue.global.js"></script>

<script>
    var vm = Vue.createApp({
        data() {
            return {
                title: "Hello",
                user: {
                    id: 1,
                    person: {pid: 1},
                    username: "yykk",
                    age: 35
                }
            }
        },
        created(){

        },
        watch: {
            title: function (newv, oldv) {
                console.log("newv:", newv)
                console.log("oldv:", oldv)
            },
            user: {
                handler: function (newVal, oldVal) {
                    console.log("newVal:", newVal)
                    console.log("oldVal:", oldVal)
                },
                deep: true,
                immediate:false // 默认不会立即加载一定改变才会触发和执行 ，如果你想立即加载，请修改为true
            }
        }
    }).mount("#app");
</script>

</body>
</html>